对位芳纶沉析纤维的制备及性能研究

Research on Preparation and Properties of PPTA Fibrid

中文关键词:  对位芳纶  沉析纤维  纳米结构  热稳定性

Key Words:PPTA  fibrid  nanostructure  property

中文摘要:

      对位芳纶（PPTA）沉析纤维因其特殊的形貌结构和力学性能可作为一种理想的增强材料。本研究基于前期合成的低分子质量PPTA溶液，探究了不同滴定剂体系中PPTA聚合物、溶剂N-甲基吡咯烷酮（NMP）、非溶剂（水或乙醇）三者之间的关系，利用沉析法制备了PPTA沉析纤维。结果表明，与H₂O-NMP滴定剂体系相比，乙醇-NMP滴定剂体系对低分子质量PPTA溶液的滴定精确度更高；利用质量分数10%乙醇-NMP滴定剂体系，通过沉析法制备的PPTA沉析纤维密度为1.41 g/cm³，比表面积最大约114.34 m²/g，长径比约570，具有明显的无定形结构，纤维结晶度为22.7%，且无玻璃化转变点及熔点，热稳定性显著。

Abstract:

      Para-aramid nano fibrid can be used as an ideal nano reinforcement material due to their unique morphology， structure， and mechanical properties. Based on the pre-synthetic solution of PPTA with low molecular weight， the relationship between PPTA polymer， solvent NMP and non-solvent （H₂O and ethanol） in different titrant systems was explored， and PPTA nano fibrid was prepared by precipitation method. The results showed that compared with the H₂O-NMP titrant system， the ethanol-NMP titrant system had higher titration accuracy for low molecular weight PPTA solution. The density of PPTA fibrid prepared by precipitation method was 1.41 g/cm³ using ethanol-NMP titrant system with ethanol mass fraction of 10%， with a maximum specific surface area of about 114.34 m²/g and a length-diameter ratio of 570. The PPTA fibrid had a clear amorphous structure with a crystallinity of 22.7%. Without glass transition or melting point， the PPTA fibrid exhibited significant thermal stability.